Case study
1200 MW combined cycle gas turbine power station
GESTRA SOLVED THE CUSTOMER ISSUES ON THE HP BY PASS STATION DESUPERHEATER
Customer
This Italian power station is part of a larger thermoelectric production park and is currently the largest CCGT of its fleet. It was first built in 1950, running on coal, oil and natural gas, and saw a site expansion in 1975. The site was completely converted to natural gas in 2005. It comprises of 1 unit with 2 gas turbines and 1 steam turbine, plus an additional unit with 1 gas turbine and 1 steam turbine, for a total generation capacity of 1200 MW.
Challenges
Soon after the plant commissioning in 2005, the customer started to face multiple challenges on the high-pressure bypass desuperheating station. Unstable steam temperature control was identified by the operational manager, with the spraywater control valve continuously chasing the set point.
Frequent replacements of the spraywater control valve trim proposed a reoccurring issue, with maintenance reports highlighting that the trim lifetime was very short, lasting only 6-7 months at a time. This resulted in high maintenance costs.
After inspections, the maintenance manager found severe cracks on the steam pipe due to thermal shock, leading to the plant having to carry out a very costly replacement of the P91 steam pipe.
Solutions
To tackle these challenges, the Italian sector sales manager shared a very positive success story from another power station within the customer fleet. He volunteered to analyse the desuperheater system performance with a high-level consultative approach.
This was highly appreciated by the plant management, and they agreed to re-size the spraywater control valve by considering both design and actual operating data. This resulted in replacing the desuperheater spraywater control valve with a zero leakage tight shut off GESTRA ZK 313.
Results
The plant saw immediate results. Due to the new robust and properly sized control valve, temperature control was significantly improved, thermal shocks were entirely eliminated from the system, and for several years the plant experienced zero-maintenance of their control valve.
Customer benefits
Improved reliability
Maximise performance
Maximise system uptime
Our success stories
By working with customers like you to understand their system, we have become trusted partners in tackling a range of challenges they have faced within their desuperheater systems, improving their system reliability, and improving their plant’s ability to meet demand.
See below how we have worked with our customers to achieve their power generation goals.
Thermal shock on your SH Desuperheater?
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